Looking for a more gentle Brightness/Contrast algorithm than the native node
The default brightness contrast node is a broken piece of anachronistic mess.
“Brightness” is exposure typically.
“Contrast” is stretching values apart or pulling them together around some image maker chosen pivot point.
So exposure is a pure multiply. Change to the CDL node and use slope.
For contrast, you can use the power of the CDL.
For a pivoted contrast, it would be correct to use a value node, and divide your RGB by the value. The value is your pivot, so for example, start with 0.18 for middle grey. Then apply the power via the CDL. Then on the other side of the node, multiply the output RGB by the pivot value. Think of the pivot as the point that values will push away from (greater “contrast”) or pull toward (“less contrast”) depending on the value of the power.
Photoshop is a display referred assumption, and formulas don’t work under the same assumptions in a radiometric-like RGB domain.